MS have not officially released it yet. but i can say with no other decoders installed (actually just nvidias purevideo dvd is installed) this worked perfect for me. MCE now plays anything i throw at it. oh i did install the divx decoder as well.
if you have any other decoders i.e. ffdshow/elecard it will interfere. the only real way to know you have a clear system is to reboot from scratch. fine if your only using pc as Htpc, and have a 8meg connection to get your hd d/ls back up to date! id definately recommend anyone having probs to start from scratch and just install your graphics card upto date drivers then the new update from mce.
i can send the file by msn if anyone wants to add me today - [email protected]